Is it a quick release or controlled release fertilizer?

I use controlled release fertilizers in all my 5-1-1 containers, and I think it works well. I use a formula that includes all the micronutrients as well as calcium: Dynamite All-Purpose Select Indoor/Outdoor, which is 15-5-9. I also use Foliage pro every week or two, but I am sometimes lax in keeping to a schedule. And with outdoor plants during rainy spells, I don't fertigate. Citruses are heavy feeders, so you probably should make sure you use enough.

I think the one I have got is controlled release (has the blue pellets. I take it this is an easy way to find out what type it is). (http://www.daltons.co.nz/home-gardening/retail-products/fertilisers/incredible-edibles-citrus-fertiliser).

Ohiofem, does your calcium not come from the lime in the mix? Also do you find you have to add slow release more frequently in 511?

I think I will have to get some sort of soluble fert as well to to them up, but there is nothing as good as foliage pro here in NZ.

There's not enough detailed information on that website to know what's in that formula in addition to NPK and magnesium. The TE is likely to be trace elements, but it would be good if you could confirm that. If not, I would assume you would need to add some trace elements. It probably does not include calcium.

The agricultural lime does supply calcium, but I like to be sure that I am supplying it in readily available amounts because, although I grow a wide variety of indoor and outdoor plants, the main plant I use the CRF on is summer tomatoes in 5-1-1, which need a lot of calcium.

How often you need to apply the CRF depends on your environment. Most CRFs release more rapidly at higher temps. So you might want to add more every two months in warm climates.

if you can supplement with a soluble fertilizer, especially one with trace elements like foliage pro, I think that would be good.

I have some trace elements that could be added to supplement this, so that might work, but it doesn't contain calcium.

You're probably OK if you use lime in your 5-1-1.

I agree with Ohiofem. 5-1-1 ratio is probably fine.

Converting lbs of Fertilizer per 100sqft to container application
rates. Ounces per cuft is the equivalent
to Grams per Liter. The volume of 100sqft at 6” depth is 50 cubic feet.

Grams of Fertilizer per liter(approx Quart or 6" pot) = ((lbs of Fertilizer
per 100sqft) *16)/50 cubic feet

Example: 5lbs per 100sqft is equivalent to 5*16/50= 80oz/50cuft= 1.6 grams per liter ( 0.32tsp)

Addition: Since a Plant in a container has limited rooting volume. You can estimate the total amount of nutrients available to a plant in the garden setting, using it's spread diameter. The area of a circle is approx 0.79 the diameter squared. Thus a 2ft diameter shrub the area under to the dripline is 3.16 sqft. The total nutrients in a season would be lbs per square foot multiplied by its rooting area. So you can increase the amount of nutrients in a container proportionally to compensate, over growing season time period.

Soil Fertility Some Average Values and misc

PPM based on the dry weight of the loam soil Sp=1.42 (Sp=1 is
about 62.4lb/cuft or 1000grams/Liter(1000 cubic cm ).

Low- N: 0-20, P:
0-12, K: 0-50

Med- N: 20-50, P:
12-25,K : 50-100

High- N:
above 50, P: over 25, K : over 100

Note: Actual amounts of the
nutrient is based the reference used for the PPM calculations. Example the 100ppm
in a water solution is less than 100ppm in loam soil. The loam amount is 1.42 times more than the water. “Sp” is the ratio of the weight of an equal volumes of a substance compared to water.

Sp Water 1.0, Sandy Loam 1.47, Loam 1.42, UC
Mix Potting Soil 0.24, and PeatMoss 0.1

Misc Note: On a Fertilizer Bag the
middle number is the percentage per weight of P2O5 in the fertilizer. The
actual P amount is about 0.437 this value. This was calculated from a periodic
table using the atomic weights of Phosphorus and Oxygen. The Phosphorous being
about 43.7% of the total weight of the compound. The same for K2O, K is about
83% of the total compound weight.

Example 100ppm Nitrogen in water
is 100 mg N per Liter, but 147 mg N in a liter of Sandy Loam soil. For water 1ppm is a 1mg/Liter.

Correction on the Previous MG Potting Soil Calculation:

Bag Label Info

2.25cuft (63.71
liters)
net weight 29.25lbs (13.26 kg)

Density 13.26/63.71=
0.208g/ml or cubic cm

Sp is approx 0.21

Nutrients N 0.21% P2O5
0.11% K2O 0.16%
6 month release

Total Nitrogen in a liter mix is 1000grams *Sp mix*.21%N= 1000*0.21*(0.21/100)= 0.441grams N per Liter ( 441ppm N total, 73.5ppm monthly@ Sp1 reference)

Duplicating using 6mo Osmocote Plus 15% N is 0.441 g/0.15= 2.94g/Liter approx heaping 1/2tsp.

Just under the 1TBS CRF per Gallon of Mix recommended in Gritty Mix Recipe.